The effect of copper addition to 2205 duplex stainless steel(DSS) on its resistance against pitting corrosion by the Pseudomonas aeruginosa biofilm was investigated using electrochemical and surface analysis techniques. Cu addition decreased the general corrosion resistance, resulting in a higher general corrosion rate in the sterile medium. Because DSS usually has a very small general corrosion rate, its pitting corrosion resistance is far more important. In this work, it was shown that 2205-3%Cu DSS exhibited a much higher pitting corrosion resistance against the P. aeruginosa biofilm compared with the 2205 DSS control, characterized by no significant change in the pitting potential and critical pitting temperature(CPT) values. The strong pitting resistance ability of 2205-3%Cu DSS could be attributed to the copper-rich phases on the surface and the release of copper ions, providing a strong antibacterial ability that inhibited the attachment and growth of the corrosive P. aeruginosa biofilm. The effect of copper addition to 2205 duplex stainless steel (DSS) on its resistance against pitting corrosion by the Pseudomonas aeruginosa biofilm was investigated using electrochemical and surface analysis techniques. Cu addition decreased the general corrosion resistance, resulting in a higher general corrosion rate in the sterile workbench, it was shown that 2205-3% Cu DSS exhibited a much higher pitting corrosion resistance against the P. aeruginosa biofilm Compared with the 2205 DSS control, characterized by no significant change in the pitting potential and critical pitting temperature (CPT) values. The strong pitting resistance ability of 2205-3% Cu DSS could be attributed to the copper-rich phases on the surface and the release of copper ions, providing a strong antibacterial ability that inhibited the attachment and growth of the corrosive P. aeruginosa biofilm.